This invention relates to novel compounds of Formula I, to compositions containing them and to their method of use as general and selective pre- and post-emergence herbicides. The invention also includes novel intermediates useful in preparing the compounds of Formula I.
Netherlands Pat. No. 121,788, published Sept. 15, 1966, teaches the preparation of compounds of Formula (i), and their use as general or selective herbicides: ##STR1## wherein
R.sub.1 and R.sub.2 may independently be alkyl of 1-4 carbon atoms; and
R.sub.3 and R.sub.4 may independently be hydrogen, chlorine or alkyl of 1-4 carbon atoms.
Compounds of Formula (ii), and their use as antidiabetic agents, are reported in J. Drug. Res. 6, 123 (1974): ##STR2## wherein R is pyridyl.
In U.S. Pat. No. 4,127,405, compounds are disclosed of the general formula: ##STR3##
R.sub.3 and R.sub.6 are independently hydrogen, fluorine, chlorine, bromine, iodine, alkyl of 1-4 carbon atoms, alkoxy of 1-4 carbon atoms, nitro, trifluoromethyl, cyano, CH.sub.3 S(O).sub.n -- or CH.sub.3 CH.sub.2 S(O).sub.n --;
R.sub.4 is hydrogen, fluorine, chlorine, bromine or methyl;
R.sub.5 is hydrogen, fluorine, chlorine, bromine, methyl or methoxy;
R.sub.7 is hydrogen, fluorine, chlorine, bromine, alkyl of 1-2 carbon atoms or alkoxy of 1-2 carbon atoms;
R.sub.8 is hydrogen, methyl, chlorine or bromine;
R.sub.9 and R.sub.10 are independently hydrogen, methyl, chlorine or bromine;
W and Q are independently oxygen or sulfur;
n is 0, 1 or 2;
X is hydrogen, chlorine, bromine, methyl, ethyl, alkoxy of 1-3 carbon atoms, trifluoromethyl, CH.sub.3 S-- or CH.sub.3 OCH.sub.2 --; and
Z is methyl or methoxy; or their agriculturally suitable salts; provided that:
(a) when R.sub.5 is other than hydrogen, at least one of R.sub.3, R.sub.4, R.sub.6 and R.sub.7 is other than hydrogen and at least two of R.sub.3, R.sub.4, R.sub.6 and R.sub.7 must be hydrogen;
(b) when R.sub.5 is hydrogen and all of R.sub.3, R.sub.4, R.sub.6 and R.sub.7 are other than hydrogen, then all of R.sub.3, R.sub.4, R.sub.6 and R.sub.7 must be either chlorine or methyl; and
(c) when R.sub.3 and R.sub.7 are both hydrogen, at least one of R.sub.4, R.sub.5 or R.sub.6 must be hydrogen.
In particular, the patent discloses orthosubstituted compounds wherein the substitution is C.sub.1 -C.sub.4 alkyl.
The presence of undesired vegetation causes substantial damage to useful crops, especially agricultural products that satisfy man's basic food needs, such as soybeans, corn, wheat and the like. The current population explosion and concomitant world food shortage demand improvements in the efficiency of producing these crops. Preventing or minimizing the loss of a portion of such valuable crops by killing, or inhibiting the growth of undesired vegetation is one way of improving this efficiency.
A wide variety of materials useful for killing, or inhibiting (controlling) the growth of undesired vegetation is available; such materials are commonly referred to as herbicides. However, the need exists for still more effective herbicides that destroy or retard weeds without causing significant damage to useful crops.